Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductor layers of materials over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon.
The semiconductor industry continues to improve the integration density of various electronic components (e.g., transistors, diodes, resistors, capacitors, etc.) by continual reductions in minimum feature size, which allows more components to be integrated into a given area. These smaller electronic components also require smaller packages that utilize less area than the packages of the past, in some applications.
During the manufacturing of the semiconductor devices, various processing steps are used to fabricate integrated circuits on a semiconductor wafer. Generally, in a photolithography process, a light source is used to transfer a geometric pattern from a mask to a light-sensitive chemical resist material that is formed on the semiconductor wafer. As a result, an exposure pattern is generated in the resist material. A series of chemical treatments may then be used to etch or otherwise transfer the exposure pattern into one or more thin film layers positioned underneath the resist layer.
Alignment is performed in photolithography process. When the mask is positioned over the wafer, its own alignment marks are aligned with the alignment marks of the wafer. Deposition of material layers on the alignment marks of the wafer may cover or blur the alignment marks and cause misalignment.
Although existing methods and devices for exposing the alignment marks have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects. Consequently, it would be desirable to provide a solution for removing a material layer from the top of an alignment mark.